golang.org/x/mod v0.40.0: module.EscapePath

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify module.EscapePath in pkg:golang/golang.org/x/mod@v0.40.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/mod@v0.40.0
Demonstrate these symbols/APIs:
  - module.EscapePath

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:e9db76a43459cea2fe9b987d646727b08a7418afce9ac5f906d9782d8d8a4e62","contract":["module.EscapePath returns lowercase paths unchanged","module.EscapePath escapes uppercase letters with exclamation prefix followed by lowercase","module.EscapePath handles multiple and consecutive uppercase letters","module.EscapePath rejects invalid paths with errors","module.EscapePath output round-trips correctly with module.UnescapePath"],"goal":"verify module.EscapePath in pkg:golang/golang.org/x/mod@v0.40.0","kind":"HOW","packages":["pkg:golang/golang.org/x/mod@v0.40.0"],"schemaVersion":1,"symbols":["module.EscapePath"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/mod@v0.40.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/mod@v0.40.0","symbols":["module.EscapePath"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/mod v0.40.0

golang.org/x/mod v0.40.0 h1:hUv+3cXcdRHz08UmSiOob7sadHig73uo5bkXxQ/tvUs=
golang.org/x/mod v0.40.0/go.mod h1:0/weTWkPWGBikyTWAX3dkjVztMmBA5hM0DH6BElSupE=

package main

import (
	"fmt"
	"log"

	"golang.org/x/mod/module"
)

// SafeModuleCachePath escapes a module path for case-insensitive file systems and proxy protocols.
func SafeModuleCachePath(modulePath string) (string, error) {
	return module.EscapePath(modulePath)
}

func main() {
	samplePaths := []string{
		"golang.org/x/mod",
		"github.com/Azure/azure-sdk-for-go",
		"github.com/GoogleCloudPlatform/cloudsql-proxy",
	}

	for _, p := range samplePaths {
		escaped, err := SafeModuleCachePath(p)
		if err != nil {
			log.Fatalf("failed to escape path %q: %v", p, err)
		}
		fmt.Printf("Original: %s -> Escaped: %s\n", p, escaped)
	}

	// Rejecting invalid module paths
	invalidPath := "/invalid/leading/slash"
	if _, err := SafeModuleCachePath(invalidPath); err != nil {
		fmt.Printf("Successfully rejected invalid path %q: %v\n", invalidPath, err)
	}
}

{
  "schemaVersion": 1,
  "goal": "verify module.EscapePath in pkg:golang/golang.org/x/mod@v0.40.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/mod@v0.40.0"
  ],
  "symbols": [
    "module.EscapePath"
  ]
}

package main

import (
	"fmt"
	"os"

	"golang.org/x/mod/module"
)

func main() {
	// Assertion 1: module.EscapePath returns lowercase paths unchanged
	lowercasePath := "golang.org/x/mod"
	escapedLower, err := module.EscapePath(lowercasePath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected no error for lowercase path %q, got: %v\n", lowercasePath, err)
		os.Exit(1)
	}
	if escapedLower != lowercasePath {
		fmt.Fprintf(os.Stderr, "FAIL: expected lowercase path unchanged %q, got %q\n", lowercasePath, escapedLower)
		os.Exit(1)
	}

	// Assertion 2: module.EscapePath escapes uppercase letters with exclamation prefix followed by lowercase
	mixedCasePath := "github.com/Azure/azure-sdk-for-go"
	expectedMixed := "github.com/!azure/azure-sdk-for-go"
	escapedMixed, err := module.EscapePath(mixedCasePath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected no error for mixed-case path %q, got: %v\n", mixedCasePath, err)
		os.Exit(1)
	}
	if escapedMixed != expectedMixed {
		fmt.Fprintf(os.Stderr, "FAIL: expected %q, got %q\n", expectedMixed, escapedMixed)
		os.Exit(1)
	}

	// Assertion 3: module.EscapePath handles multiple and consecutive uppercase letters
	camelCasePath := "github.com/GoogleCloudPlatform/cloudsql-proxy"
	expectedCamel := "github.com/!google!cloud!platform/cloudsql-proxy"
	escapedCamel, err := module.EscapePath(camelCasePath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected no error for path %q, got: %v\n", camelCasePath, err)
		os.Exit(1)
	}
	if escapedCamel != expectedCamel {
		fmt.Fprintf(os.Stderr, "FAIL: expected %q, got %q\n", expectedCamel, escapedCamel)
		os.Exit(1)
	}

	// Assertion 4: module.EscapePath rejects invalid paths with errors
	invalidPaths := []string{
		"",
		"/leading/slash",
		"trailing/slash/",
		"invalid space in/path",
		"has!exclamation/path",
	}
	for _, inv := range invalidPaths {
		if _, err := module.EscapePath(inv); err == nil {
			fmt.Fprintf(os.Stderr, "FAIL: expected error for invalid path %q, but got nil\n", inv)
			os.Exit(1)
		}
	}

	// Assertion 5: module.EscapePath output round-trips correctly with module.UnescapePath
	roundTripPaths := []string{
		"example.com/User/Repo",
		"github.com/Sirupsen/logrus",
		"golang.org/x/tools/gopls",
	}
	for _, path := range roundTripPaths {
		esc, err := module.EscapePath(path)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: EscapePath failed on %q: %v\n", path, err)
			os.Exit(1)
		}
		unescaped, err := module.UnescapePath(esc)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: UnescapePath failed on %q: %v\n", esc, err)
			os.Exit(1)
		}
		if unescaped != path {
			fmt.Fprintf(os.Stderr, "FAIL: round-trip mismatch: original %q != unescaped %q\n", path, unescaped)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: module.EscapePath contract passed")
}